Upon Sr (hole) doping, the number of conduction electrons may be reduced,
while that of holes increases. The Kondo physics may be suppressed and
replaced by the usual \(t\) -\(J\)  model for large hole doping, resembling the
physics of cuprates. On the other hand, for electron doping, we may expect
to first recover the AF long-range order with reduced hole density, and then
with increasing conduction electrons and Kondo screening, the AF order will be
suppressed again and the system turns into a heavy fermion metal with sufficient
electron doping. SC may emerge around the quantum critical point. Whether or not the AF phase may actually exist depends on
how doping changes the fraction of electron and hole carriers. But in bulk Nd\(_{1-x}\) Sr\(_x\) NiO\(_2\) , NMR experiment has revealed short-range glassy AF
ordering, supporting the possible existence of antiferromagnetism [1]}. Figure REF  summarizes possible ground states of the
model on the temperature-doping plane, showing a connection between the
heavy fermion and cuprate physics on two ends and the nickelates in between.
However, it should be noted that current experiment on “overdoped"
nickelate superconductors found a weak insulator rather than a Fermi liquid
as in heavily hole-doped cuprates [2]}. How exactly holes are
doped in Nd\(_{1-x}\) Sr\(_x\) NiO\(_2\)  remains an open question.
